Approximately 90% of individuals with NIDDM are overweight. Overweight can exacerbate the course of the disease and co-morbid conditions, increasing health care utilization, morbidity, and mortality. Clinic-based programs for weight management are costly and serve only a small percentage of at risk individuals. Thus, population-based behavior change programs may be necessary to reach larger percentages of at risk individuals more cost- effectively. Preliminary research on the application of the Transtheoretical Model (TTM) to health behaviors involved in weight management suggests that the model has the potential to guide the development of effective multiple-behavior interventions. Phase I of this Fast-Track proposal involves the customization and feasibility test of a stage-matched, individualized, interactive intervention based on the TTM. Feasibility includes proactively recruiting 50% of eligible participants (n=300) to participate in a randomized clinical trial of a comprehensive weight management expert system intervention and evaluating acceptability of the intervention materials. Computerized expert system interventions and stage-matched manuals delivered proactively to entire populations can have unprecedented impacts on the targeted health behaviors as well as weight. Using the TTM as the basis will provide the theoretical and individualized framework that experts in the area have indicated is necessary to develop more effective and cost- effective interventions. PROPOSED COMMERCIAL APPLICATIONS: Overweight and obesity are costly to all participants in the health care delivery system. Over 90% of the 15 million adults with NIDDM are overweight, which increases healthcare utilization, morbidity, and mortality. Effective population-based weight management interventions that are appropriate for people at all stages of change have the potential to have significant health and financial impacts, as well as tremendous commercial potential.